The morning that James Wade Sweatt first tried a powdered caffeine supplement, his heart went into cardiac arrest. For the next 11 days, he was in a coma. Despite efforts to save him, the 24-year-old Alpharetta engineer died.

Now, nearly four years after his death, the federal Food and Drug Administration has announced a crackdown on highly concentrated caffeine products, saying they pose a significant public health risk. The agency said Friday that dietary supplements containing highly concentrated caffeine in powder or liquid forms are now considered illegal, and it is prepared to take immediate steps to begin removing them from the market.

Such action has been the goal of Sweatt’s parents, who have worked for years along with the parents of another young victim to try to stop companies from selling the products.

“The people who sell it had been warned, and they just continued to do it,” said Julie Sweatt, of Gardendale, Ala.

“We have been to Washington and spoken to the FDA and pleaded with them to save other lives by banning the caffeine powder,” she said. “Our goal in all this — we already had lost our son and could not bring him back — was to make sure no other family went through what our family went through.”

The FDA has repeatedly taken action against the concentrated caffeine products in the past, but it noted that they continued to be marketed to consumers as dietary supplements, often over the internet, and sold in bulk quantities, with up to thousands of recommended servings per container. It is nearly impossible to accurately measure those products, the agency has said.

“The amounts used can too easily become deceptively high because of the super-concentrated forms and bulk packaging in which the caffeine is being sold,” said FDA Commissioner Scott Gottlieb in a prepared statement.

A single teaspoon of a highly concentrated caffeine powder can be a toxic dose, containing as much caffeine as 20 to 28 cups of coffee, the agency said.

Wade Sweatt and Logan James Stiner, an 18-year-old high school senior who also died in 2014, were otherwise healthy young men. Wade was a newlywed who had just begun a job in the Atlanta area. Logan was prom king and an athlete at his high school.

The caffeine supplements they bought were marketed as a way to boost energy, and the young men believed a caffeine supplement would be safe, the families have said.

“We don’t teach our kids that caffeine can kill you,” Julie Sweatt said.

While the FDA’s announcement noted only the two men’s deaths, Sweatt said that other caffeine-related deaths may go unrecognized.

“When someone dies of a caffeine powder or caffeine-related overdose, it comes up as a cardiac arrest,” she said.

Unless someone knows that the person has taken a caffeine product, as happened in her son’s case, tests would not be done during autopsy for the substance.

Deaths related to dietary supplements also can go unrecognized because FDA learns about serious health issues through a process that largely relies on individuals to voluntarily report adverse events. And unlike prescription drugs, supplements can be legally sold without companies' first providing proof they are safe and effective.

The FDA sent warning letters in 2015 to companies in North Carolina, Oregon, California and Nevada marketing the products, and in 2016 warned companies in Illinois and Minnesota. The FDA warned that the supplements presented a significant or unreasonable risk of injury or illness under the use suggested in labeling, or that the products were being promoted for conditions that cause them to be considered a drug.